As three-dimensional video recognition system using glasses, there are known an anaglyph system, a passive glass system (hereinafter may be referred to simply as passive system), an active shutter glass system (hereinafter may be referred to simply as active system), and the like. In the anaglyph system, the display quality is extremely low, and so-called cross talk is caused. In each of the passive system and the active system, polarizing glasses are used. Hereinafter, the polarizing glasses used in the active system are also referred to as active shutter glasses.
In the passive system, the polarizing glasses themselves can be manufactured to be lightweight and inexpensive, but in order to generate the left-eye and right-eye images, it is necessary to use pixels separately for each of the left-eye and right-eye images. For this reason, at the time of three-dimensional video display, the spatial resolution, which is two times the resolution in the case of usual two-dimensional video display, is required, and hence the resolution of three-dimensional video is generally low. Also, the display quality is also low as compared with the active system. Further, birefringent layers, such as a λ/2 plate and a λ/4 plate, need to be patterned and formed in each of the pixels, which results in an increase in the cost of the video display device.
On the other hand, the active system is excellent in display performance. For example, in the case where a video display device has a resolution of full high-vision (1920×1080), three-dimensional display can be performed with the resolution of full high-vision as it is. Further, as the performance required for the video display device of the active system, a high frame rate and high-performance image processing are required, and these requirements can be satisfied even by an existing high-end video display device. That is, even in the stage before the spread of 3D contents, the existing high-end video display device can be used as a video display device capable of 3D display without incorporation of a special member into the video display device itself.
Specifically, for example, as described in Patent Document 1, a technique is disclosed which uses active shutter glasses, each having a pair of polarizers and a liquid crystal provided between the pair of polarizers. Further, a technique is disclosed which utilizes a first polarizing filter arranged on the display surface, a second polarizing filter arranged in front of each eye of the observer, and a liquid crystal inclusion body provided between the both polarizing filters (see, for example, Patent Document 2).
Further, from the viewpoint of design improvement, a protective plate is often arranged in front of the screen of not only the video display device for three-dimensional video recognition system but also a recent TV display screen.
Further, in recent years, a touch panel is often arranged as input means in front of the screen of various electronic devices, such as portable terminals, such as a portable telephone and a PDA (Personal Digital Assistants), an electronic notebook, a personal computer, a copying machine, and a terminal device for game.